1. Field of the Invention
The present invention provides a composition obtained by organic solvent extraction of defatted plant seed which is an atherosclerosis preventative agent. The present invention further provides a food and a pharmaceutical composition containing the composition, as well as a method of preventing an atherosclerotic disease.
2. Discussion of the Background
Along with the westernization of life style in recent years, in addition to cancer, atherosclerotic diseases such as angina pectoris, intermittent claudication, cardiac infarction, cerebral infarction and the like have become the main causes of death of Japanese people. Once developed, these diseases are very difficult to cure, and dramatically degrade “quality of life.” It is undisputable that a countermeasure to prevent or control the progression of atherosclerotic diseases is extremely important from a social standpoint as well.
A consensus has been generally reached that oxidation of low density lipoprotein (LDL) plays a key role in the early stages of lesion formation. As such, the importance of not only controlling the blood cholesterol level to a suitable range but also suppressing the production of oxidized LDL has been recently noted. It has been determined that certain foods, particularly a food derived from plants, contain an abundance of anti-oxidative substances. To this end, the anti-oxidative substances contained in green tea and red wine are considered to be taken into LDL (or in the vicinity thereof) and eliminate radical to prevent production of oxidized LDL (Fuhrman et al, Am. J. Clin. Nutr., 61: pp 549-54, 1995). There is also an epidemiological study that concludes that positive intake of these foods suppress cancer and heart diseases (Renaud et al, Lancet, 339: pp 1523-26, 1992).
In the meantime, there is a report that particular components derived from particular seeds such as sesame seed lignan, grapeseed polyphenol and the like show an anti-atherosclerotic activity with experimental animals (Kang et al. J. Nutr., 129: pp 1885-90, 1999; Yamakoshi et al, Atherosclerosis 142: pp 139-49, 1999). However, the anti-atherosclerotic property of a plant seed component has only been determined at an animal test level in a few cases, and many researches remain at a test tube level.
For example, JP-A-8-337536 discloses an anti-active oxygen agent extracted from a roasted and then fermented plant seed. The technique described in JP-A-8-337536 uses a plant seed as a starting material, but has low versatility because it requires operations such as roasting, fermentation treatment and the like, and, thus, this technique is not practical. In addition, no evidence exists that a fermented plant seed obtained by this method has an effect on suppressing atherosclerosis.
In another study, Zhang et al (Chem. Pharm. Bull., 45: pp 1910-14, 1997) report structures of a group of compounds extracted from a safflower oil cake by distribution of various solvents, and that some of these structures have an antioxidant activity in vitro. However, it is not clear at present if such compounds having an antioxidant activity are effective for preventing atherosclerosis. In consideration of the fact that antioxidant activity in vitro is known not to be necessarily correlated to the anti-atherosclerotic activity in living organisms (Fruebis et al, J. Lipid Res., 38: pp 2455-64, 1997, Fruebis et al, Atherosclerosis 117: pp 217-24, 1995, Munday et al, Arterioscler. Thromb. Vasc. Biol., 18: pp 114-19, 1998, Wagberg et al, J. Pharmacol. Exp. Ther., 299: pp 76-82, 2001), confirmation of whether or not an anti-oxidative substance in a plant seed has anti-atherosclerotic property is required at least at an experimental animal level.
Therefore, in view of the state of the art and the ever increasing medical concerns over atherosclerotic diseases, there remains a critical need for compositions that are effective atherosclerotic disease preventatives.